The present invention relates to a semiconductor device and a method of manufacturing the same and can be suitably used for, for example, a semiconductor device having a trench portion and a method of manufacturing the device.
There is a semiconductor device having an element isolation structure obtained by forming an insulating film in a trench portion formed in a surface as the main surface of a semiconductor substrate. There is also a semiconductor device having an element isolation (deep trench isolation: DTI) structure obtained by forming an insulating film in a trench portion having, as an aspect ratio, that is, a ratio of the depth of the trench portion to the width of the trench portion, an aspect ratio as high as 1 or more.
Japanese Patent Laid-Open No. 2011-66067 (Patent Document 1) discloses a semiconductor device equipped with a trench formed in the main surface of a semiconductor substrate so as to surround, in a plan view, an element formed on the main surface of the semiconductor substrate and an insulating film formed on the element and in the trench; and a method of manufacturing the semiconductor device. According to the technology described in Patent Document 1, the insulating film is formed so as to cover the upper portion of the element and at the same time, to create a space in the trench.
Japanese Patent Laid-Open No. 2013-222838 (Patent Document 2) and Japanese Patent Laid-Open No. 2011-151121 (Patent Document 3) disclose a semiconductor device equipped with a semiconductor substrate having a support board, a buried insulating film, and a semiconductor layer stacked one after another in order of mention, a trench formed in the main surface of the semiconductor layer, and an insulating film formed in the trench; and a method of manufacturing the semiconductor device. According to the technology described in Patent Document 2 and the technology described in Patent Document 3, the trench is formed so as to surround, in plan view, an element formed on the main surface of the semiconductor layer. According to the technology described in Patent Document 2 and the technology described in Patent Document 3, the insulating film is formed so as to cover the upper portion of the element and at the same time, to create a space in the trench.